BlackBerry's weight loss app has helped a waitress in UK to shed seven-and-a-half stone in just 10 months.
Shelli Henderson, from St Albans, Herts, dropped from 18st to 10st 7lb - thanks to a 1.99-pounds calorie-counting programme downloaded on her high-tech phone, reports The Sun.
The 22-year-old had struggled with her weight since leaving school at 16 and was an unhappy size 22.
Shelli used the app to tot up her calorie intake by entering the food she ate each day.
She quickly became hooked and by combining the information with regular exercise the weight started to melt away.
"I downloaded the counter on a whim to try it for a week. The pounds dropped off so I kept going," said Shelli, now a size 12.
"I worked out that if I wanted to stay full without going over my target I had to change what I ate. As a waitress there was food constantly available. I started the day with a full English breakfast and grazed all day on chips," she added.
Shelli has been promoted to bar manager at her restaurant and she puts it down to her slimmer physique.
"I love my new-found confidence. I even booked my first girlie holiday this summer and bought my first bikini. My self-esteem used to be at rock bottom. I made excuses not to go out because I felt embarrassed," she said.
"The calorie counter helped me to change my eating habits. It was really easy to use. After seeing my results, I encouraged some of my friends to copy my technique, and the outcome for them has been amazing too," she added.